A series of 2-pyrazolines
5–
9 have been synthesized from
α,β-unsaturated ketones
2–
4. New 2-pyrazoline derivatives
13–
15 bearing benzenesulfonamide moieties were then synthesized by condensing the appropriate chalcones
2–
4 with 4-hydrazinyl benzenesulfonamide hydrochloride. Ethyl [1,2,4] triazolo[3,4-
c][1,2,4]triazino[5,6-
b]-5
H-indole-5-ethanoate (
26) and 1-(5
H-[1,2,4]triazino[5,6-
b] indol-3-yl)-3-methyl-1
H-pyrazol-5(4
H)-one (
32) were synthesized from 3-hydrazinyl-5
H-[1,2,4]triazino[5,6-
b]indole (
24). On the other hand ethyl[1,2,4]triazolo[3,4-
c][1,2,4]triazino[5,6-
b]-5,10-dihydroquinoxaline- 5-ethanoate (
27) and 1-(5,10-dihydro-[1,2,4]triazino[5,6-
b]quinoxalin-3-yl)-3-methyl-1
H-pyrazol-5(4
H)-one (
33) were synthesized from 3-hydrazinyl-5,10-dihydro-[1,2,4]triazino[5,6-
b]quinoxaline (
25) by reaction with diethyl malonate or ethyl acetoacetate, respectively. Condensation of 6,6-dimethyl-4-
oxo-4,5,6,7-tetrahydro-1
H-indole-2-carbaldehyde (
1') with compound
24 or
25 afforded the corresponding Schiff's bases
36 and
37, respectively. Reaction of the Schiff's base
37 with benzoyl hydrazine or acetic anhydride afforded benzohydrazide derivative
39 and the cyclized compound
40, respectively. Furthermore, the pyrazole derivatives
42–
44 were synthesized by cyclization of hydrazine derivative
25 with the prepared chalcones
2–
4. All the newly synthesized compounds have been characterized on the basis of IR and
1H-NMR spectral data as well as physical data. Antimicrobial activity against the organisms
E. coli ATCC8739 and
P. aeruginosa ATCC 9027 as examples of Gram-negative bacteria,
S. aureus ATCC 6583P as an example of Gram-positive bacteria and
C. albicans ATCC 2091 as an example of a yeast-like fungus have been studied using the Nutrient Agar (NA) and Sabouraud Dextrose Agar (SDA) diffusion methods. The best performance was found for the compounds
16,
17,
19 and
20.
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